nasty big pointy teeth…

the case.

A 2 year old infant is bought to your ED with a painful right hand. She claims to be have been bitten by the family dog 2 days earlier…


She is afebrile & systemically well. Her digits are neurovascular intact.

[DDET What are your concerns with this case ?]

Considerations & concerns in patients with bite injuries include;

  • Identification of injuries inflicted by the bite ?
  • Prevention & treatment of local bacterial infection.
  • Prevention, recognition & treatment of systemic illnesses.

Dogs are capable of exerting ~200 pounds per square inch into their bite !!

  • Skin & soft tissue injuries are typically extensive, but may range from contusion & haematoma to large gaping lacerations with tissue loss. Punctures occur less often.
  • Nerve & tendon injuries are rare but can occur (more common in bites from police dogs).
  • Associated crush injuries can result in fractures.

Only ~5-10% of dog bites become infected.

  • Bites to the hand however have a higher risk of infection (~12-30%)
  • Dog bites are polymicrobial and include;
      • Strep & staph species
      • Pasteurella
      • Anaerobes
      • Capnocytophaga canimorsus. 

Specifically for our patient…

  • The wound already appears inflamed/infected.
  • This is a delayed presentation.
      • What first aid was there?
      • Irrigation will be difficult and potentially futile (auto wound closure).
  • Are there child safety issues here ?


[DDET What are your principles of management ??]

  •  Primary survey – assessing for the presence of life-threatening injury.
      • Especially in young children or mauling by large (or several) animals.
      • Includes control of bleeding.
  • Meticulous examination.
      • Determination of extent of underlying injury.
      • Is there evidence of neurovascular compromise?
      • Is there involvement of joint space or tendon?
      • Arrange x-rays if concern for fractures.
  • Cleansing, decontamination & debridement.
      • Aggressive irrigation.
      • Debridement of devitalised tissue.
  • Analgesia.
  • Tetanus prophylaxis.


[DDET Can any of these wounds be closed immediately ??]

If a patient & their injury match the following, there is a < 5% risk of post-repair infection.

  • Location: face or scalp
  • Injury within 6 hours
  • Simple laceration appropriate for single-layer  closure. (ie. no devitalised tissue)
  • No underlying injury (eg. tendon or fracture)
  • No immunosuppression (diabetes, AIDS, chemotherapy).


[DDET Who requires antibiotics ?]

  • Those with established infection.
  • Any injury undergoing surgical repair.
  • Delayed presentation (>6-8 hours).
  • All cat bites.
  • Deep dog bite punctures.
  • Hand wounds.
  • Wounds with underlying structures involved.
  • All bites in the immunocompromised host.


[DDET Which antibiotics should we use ??]

  • Low risk oral therapy:
      • Amoxycillin + clavulanate for 5 days.
  • High risk therapy:
      • Piperacillin + tazobactam (OR)
      • Ticarcillin + clavulanate   (OR)
      • Metronidazole + Ceftriaxone / Cefotaxime.

I acknowledge that antibiotic therapy will vary from country to country & between local facilities.
This is our recommended guideline.


[DDET The follow-up…]

So if we apply the above risk-stratification to our little patient. She is a delayed-presentation bite to the hand and this is what happened when she tried to ‘make a fist’ …


Her x-ray excluded fractures.

With concern for deeper tissue involvement she was started on cefotaxime & metronidazole. The following morning she underwent a debridement & washout in the operating theatre.


[DDET How about something light-hearted…??]



[DDET References.]

  1. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th Edition.
  2. Rosenʼs Emergency Medicine. Concepts and Clinical Approach. 7th Edition.
  3. Therapeutic Guidelines. “Skin and soft tissue infections: bites and clenched fist injuries.”




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